In recent years, various lighting fixtures utilizing a light emitting diode (LED) serving as a light source have been commercialized. LEDs can provide higher luminance, and operate with low power consumption, and accordingly, are expected to serve well as a light source for use in vehicle lights for next generation lighting applications. In Japanese Patent No. 4115921 (corresponding to U.S. Pat. No. 7,387,417), a vehicle headlamp for low beam is proposed that has LEDs serving as light sources and forms a luminous intensity distribution pattern for a low beam, as illustrated in FIGS. 1 and 2. Note that FIG. 1 is a front view of the vehicle headlamp, and FIG. 2 is a longitudinal cross-sectional view of the vehicle headlamp (taken along II-II line in FIG. 1). The vehicle headlamp 9100 in the drawings can be installed on the right side front end of a vehicle body (namely, near the opposite lane when travelling on a left lane). The vehicle headlamp 9100 includes a lamp body 9102 having a front opening, and a light-transmitting cover 9104 attached to the front opening of the lamp body 9102. The lamp body 9102 and the transparent cover 9104 can define a lamp chamber. The vehicle headlamp 9100 further includes six optical units (lighting units) 9110 and 9112 which are housed in the lamp chamber and supported by a supporting bracket 9120 so that three of them are arranged in an upper portion thereof and the remaining three of them are arranged in a lower portion (in a two-stage arrangement).
The light-transmitting cover 9104 is attached to the lamp body 9102 so as to cover the entire front opening of the lamp body 9102. In the lamp chamber, an inner panel 9106 is provided along the light-transmitting cover 9104. The inner panel 9106 has cylindrical openings 9106a and 9106b at positions corresponding to the respective optical units 9110 and 9112, so that the cylindrical openings 9106a and 9106b surround the corresponding optical units 9110 and 9112.
These six optical units 9110 and 9112 can project light so as to form a light distribution pattern for low beam (a so-called passing-by beam). The optical units 9110 are disposed so as to be directed in the front direction of a vehicle body, thereby serving as lighting units for front illumination. The optical units 9112 are disposed so as to be directed sidewards in the width direction of a vehicle body by a predetermined angle with respect to the front direction, thereby serving as lighting units for sideward illumination.
Although a detailed description will be omitted here, each of the optical units 9110 for front illumination can be a projector type lighting unit, and includes: a projection lens 9132 disposed on an optical axis Ax extending in the front-to-rear direction of the vehicle body; a semiconductor light emitting device 9130 disposed on the optical axis Ax in the rear of the projection lens 9132; a reflector 9134 disposed so as to cover the semiconductor light emitting device 9130 from above; and an optical controlling member 9136 disposed between the semiconductor light emitting device 9130 and the projection lens 9132.
The semiconductor light emitting device 9130 can be a white light emitting diode having a light emission chip, for example. The light emitted from the semiconductor light emitting device 9130 upward can be reflected by the reflector 9134 to the front side near the optical axis Ax, so that the light can be projected through the projection lens 9132 in front of the optical unit 9110. The optical controlling member 9136 has a front edge 9136a disposed near the rear focus of the projection lens 9132. The light entering the front edge 9136a or lower portion of the optical controlling member 9136 can be shielded so as not to enter the projection lens 9132, thereby forming a bright/dark boundary line (cut-off line) at the upper edge of the light distribution pattern formed by the light projected slightly downward from the projection lens 9132.
The optical unit 9112 for sideward illumination can be a reflector-type (parabola-type) lighting unit, and includes three semiconductor light emitting devices 9150 arranged in the vehicle width direction, and a parabolic cylinder-like reflector 9152 disposed below these semiconductor light emitting devices 9150.
The semiconductor light emitting device 9150 can be a white light emitting diode having a light emission chip, for example. The light emitted from the semiconductor light emitting device 9150 downward can be reflected by the reflector 9152 to the front side, so that the light can be projected in front of the optical unit 9112. As the reflecting surface of the reflector 9152 is constituted by the parabolic cylinder-like surface and directed slightly downward, the projected parallel light is directed slightly downward in the vertical direction, but the light can be diffused in the lateral direction.